The present invention relates to image processing systems and methods, and more particularly to image processing systems that process images with regions representing target objects.
Image registration is an image processing technique for combining two or more images, or selected points from the images, to produce a composite image containing data from each of the registered images. During registration, a transformation is computed that maps related points among the combined images so that points defining the corresponding structures in each of the combined images are correlated in the composite image.
Image processing techniques suitable for image registration follow two different approaches. The first requires that an individual with expertise in the structure of the object represented in the images label a set of landmarks in each of the images that are to be registered. For example, when registering two MRI images of different axial slices of a human head, a physician may label points, or a contour adjacent to these points, corresponding to the cerebellum in two images. The two images are then registered by relying on a known relationship among the landmarks in the two brain images. The second currently-practiced technique for image registration uses the mathematics of small deformation multi-target registration and is image data driven. Here, volume based imagery is generated of the two targets from which a coordinate system transformation is constructed.
Conventional image processing techniques may not adequately take into account the existence of anomalies in an image that can limit performance when registering target images with corresponding atlas images that do not contain representation of anomalies. There is, therefore, a need for an image processing system that overcomes the limitations of the conventional techniques.
The present invention provides a methodology for image processing that can compensate for the presence of target objects in images.
Additional features and advantages of the invention will be set forth in the description which follows, and in part, will be apparent from the description, or may be learned by practicing the invention. The objectives and other advantages of the invention will be realized and obtained by the method and apparatus particularly pointed out in the written description and the claims hereof as well as in the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described, a method and apparatus according to the invention registers a first and a second image, where the second image contains a target object. The method comprises the steps of identifying a region in the second image containing one or more image data elements representing the target object, transforming the second image to reduce the size of the region containing the target object, and registering the first image and the second image.
Another embodiment consistent with the present invention registers a first image and a second image. A method comprises the steps of identifying a region in the second image containing one or more image data elements representing a target object. After identifying this region, the first and second images are registered using a first transform component that filters one or more data elements in the second image that are contained in the identified region, and a second transform component that includes one or more data elements in the second image that are contained in the identified region.
Both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.